Furnace



Patented .i'a `n .1,1929.- y

UNITED STATES'PATENr oF JOHN E. MUHLEEED, or SCARSDAEE, AND VIRGINIUS z.. cRAcRISTI, or RRoN'zwI'LLE.4

NEW YORK, 'A'SSIGNoRs B`Y MESNE ASSIGNMENTS, To LoPULoo SYSTEMS, INC., or NEW YORK, N. Y.,A CORPORATION oF DELAWARE.

EURNAE.

Application fiiea February 25, 1519. seriai Nq. 279,155.

The present invention relates -to improvements in furnaces, the present disclosed embodiment relating particularly to bo`iler fur.- naces in'whichpulverized fuel is burned.

It is an object of this invention to provide 1n a furnace increased 'radiating surfacesso disposed as to aid in the combustion, such radiating surfaces being perpendicular, preventingthe accumulation of ash or other heat absorbing refuse thereon to render them at all times regenerative, and in this manner. maintaining at all times afull eliciencyfof the so as to aid in the, combustion, permitting of the efficient burning of either low or high Volatile fuelswitlout rap-id destruction-of the refractories andjot-lier difficulties and also providing an increased flameway.

It is a further object to provide a furnace in whichthefeeding. and mixing with air is arranged in consecutive steps, whereby a small proportion of the air necessary for combustion is induced'.into the furnace downwardly with the fuel and iI`i` line withthe in-.

coming fue-l substantially iii a perpendicular direction, and yin which the additional air necessary -for combustion is induced in the diis'obtained.,l A

vstructure which -can be maintained in proper rection transverse to Said first mentioned' cury rent, the resultant'currentsffrom the perpendic'ular, and transverse currents, thereby insuring thorough mixing of air f or combustion, so that the greatest efficiency in mixing further object is' to create a condition with facility and without interfering with the operation thereof.

A still further object 4is -to provide'preliminary and secondary combustion areas or process of combustion which isa poor heat conductor, belowthe combustion' zones, which zoneI below substantial slagv zones into which combustion air may be"in-.

dependently directed, thereby improving the and to provide a neutral' zone of air,

of air will cool the ash forming temperature.

One of'the principal functions of the furnace isthe provision of a construction whereby the combustion is completed at a point removed from the space provided for the deposit and-removal of ash, so as to have an 'in- 'tervening non-conducting volume of air or air zone, between the space in which the combustion takes place and the lashes or floor on which the deposit of ash accumulates, so as to maintain the-temperature in said Abelow thef melting venting the formation of slag.

'embodiment of our pei-imposed air feed pipes are With theseand other, objects in view an invention is shown in the ac cimpanying drawing and this embodiment wi with reference thereto and the invention will 'befinally pointed out. in the claims.

'In the drawings, Y

Fig. 1 represents in vertical section a Afurnace of the boiler type embodying one forml of our invention;

ig. 2 is a transverse sectional view taken Vthrough the line 2-2 of Fig. 1

Fig. 3 is a 'similar sectional view.` (with parlts broken away) showing a modified form; anc

ash space' point of ash, thereby prebe hereinafter more fully described 1,697,688 N, FICE.

Fig. 4 is a fragmentary vertical section of l a still further modified form.

v Similar reference characters indicate corresponding parts throughout the4 severalgures of the drawings.

'Referring to Fig. 1 of the drawing, the furnace, shown l therein comprisesa combustion chamber 10 having a forwardly projecting mixing chamber 1l, in the top wall 12 of which there isdisposed one or a plurality of fuel feed burners 12a through which pulver- 4ized fuel mixed with air is fed by'meansbf the apparatus 14 which receives the lfuel from the bin 15 and is operated through the motor 16. Any 'suitable'nuinber and arrangement fof. theseburners may' be provided upon the capacity of the furnace. In the perpendicular front wall 13 of the vmixing cl'iai'iiberlthere are provided aqplurality 'of horizontally disposed auxiliary air feedfpipes or openings v14 provided with controlling dampers 15.

openings llEl may also'be located in thefperpendicular side walls 13,vwhich divergefrom the front wall to ,the parallel side walls sothat incoming fuel and air flow in close contact therewith, these walls following the natural spread" of the body of flame.' Two such sushown. in the drawing, but it will vbe understood that any depending Auxiliary' air feed pipes o r I number of these may be 'arranged along the length of ',the chamber. .i The vertical feed burners 12? are preferably of a type as disclosed in ounce-pending application, Serial No. 215,428,1iled February 5th, 1918, and opposed thereto and below necessit to the o eration of our furnace.

provided a aterally dis fiecting the incoming air feed pipes 14', there may be osed'target wall 16 rom an opening 17.

the auxiliary inclined downwardly provided with a door fuel into t e furnace. This target wall is, liowever, by no lmeans a perpen icular ba e or artition wall 19 depends fromethe top wall112 terminating at apoint above the target wall 16",. this wall separating the preliminary combustion area of the mixing chamber from the secondary combustion area respectively indicated at20 and 21, an outlet space connecting the two areas v beingy disposed between thecornerfornied bythe target wall 16 andthe vertical lower .wall 22 and the lower end of the depending baflle wall 19.

Inclined upwardly from'the lower vend of the lower vertical wall 22, there is provided a guide wall 23 forming the floor of the secondary combustion area 21 and being substantially opposed to thev direction of fiow-of the Afuel emanating from the outlet space between 4 the preliminary and the secondary combustion areas. At the lower end of 4the wall 22 there isl provided an outlet 24 having a door 25 for the removal of ash.

A plurality of horizont llly disposed auxiliary air feed pipes 26 'having controlling dampers 27, may be provided in the'lower Awall 22 which admit air into the secondary -combustion area.

The boiler 28 to be heated is arranged across the combustion chamber, this, however,

l'beine' an arbitrar arrangement and other other heat absorbing refuse.

surfaces of the walls 19 and 13 being per en-Y theaccumulation of as or The transverse streams of air entering through the openings 1:4 tend to break up the surrounding layer dicular prevent of consumed gas permitting additional air to come into intimate contact with the partially consumed gas in the core of the flame causing complete combustion. The baffle wall 19, it will be seen, provides an increased radiating surface and. flame-way along one side of which'the fuel combustion area and along the other side of which it {iows through the secondary combus- 18, this targlet wall del from the feed flows through the preliminary tion area providing in each case perpendicular heat radiating surfaces.

Where the target wall 16 is used, the 'bricks of which it is composed, because of, its intenseheatand the impingement of the fuel thereon, burn out and otherwise become affected so', Vthat renewal becomes necessary.

renewal or repair of such parts necessitated the putting out of operation and complete cooling of the furnace. According to the present invention renewal of the target walll surface is permitted during'operation of the furnace through the opening 17, this opening Heretofore l permitting insertion of the bricks by asuit-A able tool or the bricks may be thrown therein, thereby providing a new surface. The ash let 24 where they may be removed.

The intervening distance between the target wall 16', and the space to decrease the temperature the melting point of ash, ash in a free state will he precipitated in such place,fand such material is kept cleaned out-of the 'furnace proper, the flame not impinging upon such noli-combustible or non-radiating solids in 29, being sufl'icientto a point below -and other precipitated products ofA combus- .tion` slide along the inclined wall 23 tothe outview ofthe intervening air zone of poor heat j conductivity. This intervening'zone constitutes in effect anexcess body of air which may be termed a neutral zone and -it acts, l

among other things, to prevent material fusion -of those products of` combustion which precipitate so ,that forming a mass of slag'in the lower portion of the furnace difficult of removal.

In'applying'pulverized fuel burning equipment to steam generating plants it is hi 'h y 'important to prevent slagging of the evaporating surfaces. If this is not prevented efficient steaming cannot behad because the slag forms an insulating coating, as it weie, which ydoes not permit' the ready absorption ofthe heat. In our furnace slagging difliculties whiehhave been so troublesome in this branch of the art'are completely overcome. The flames do not carry along with them those products of combustion which slag as they do in all previous furnaces with which we are fan'iiliar. These products are fuse and form' they are prevented from given a chance to precipitate because of the low velocity atl which 'they are carriwed through the'furnace, and because of the neutral zone of air `through which they rfall they' .do not fuse and form a solid mass of slag in the bottom. ofthe furnace incapable moval. n

In Fig.' 3 we have illustrated a modified form of construction -in which the fuel feed burners 1.2iL have their outlets disposed adjacent. and contiguous to the inner side of the front wall 31, which in this form extends ,uninterrupted to the base of the ash pit, in which the ashes 32 are precipitated, the said wall being provided at suitable point-s with-auxilof re- 'dispensed with in the showing of this form,

i if desired, be used although itiwillbe understood that'it may,

along the perpendicular wall in intimate relation with the radiating heat therefromindicated by the arrows 30, the increased radiating surface greatly aiding combustion, the

- perpendicular disposition of the radiating surface preventing ycof 'neetion with the front Arelation to the form shown in Fig. 1. It will .20 b

the accumulation of ash or other heat absorbing refuse. Q

In- Fig. 4a somewhat similar construction to that shown inV Fig. 3 is shown, butin this target wall 16', is included in conwall 13 in asimilar form the e understood that in 'either of these forms shown in Figs. 3 and 4 a' partition o r baffle wall 19, such -as shown in Fig.l 1 may be in` eluded, 'and' that this wall in any of the embodiments lmay 'be positioned at any desired distance from the front wall according to the degree of intimacy desired between t-lie ineoin.- :ifng fuel and air andthe heat radiating sur-I aces.

Tehave illustrated and described a preerred and satisfactory,embodiment of our invention but it is be made therein within the spirit and scope thereof as defined in the appended claims.

We makeno claim herein to the process of burning the pulverized fuel'described, but have claimed .the same in our copending, application,-Serial-,No. 321,97 6, filed September 5, 1919, which is a division hereof.

- e'claim:v v j 1. A furnace for burning `pulverized fuel having means for admitting the fuel substantially vertically downward, andan internal radiating wall lin proximity to a wall of the furnace between which' Walls the burning fuel passes downward, said furnace being constructed to provide a coolingzone inteimediate the Zone at which combustion takes place and t-he 'ash deposit, said cooling zone acting to cool the ash precipitating therethrough sufficiently to prevent substantial fusion of the ash.

9 Afurnace for burning pulverized fuel having means for admitting the fuel substantially vertically downward adjacent to asublstantially vertical radiating wall thereof,

p said furnace being constructed to provide a cooling zone intermediate the zone at which combustion takes' place and the ash deposit, said cooling zone acting t-o cool the as h'precipitating therethrough sufficiently to prevent substantial fusion fof the ash.

3. A furnace for burning pulverized fuel having an outlet in' an upper part and having means for admitting the fuel in an upper part of the chamber in a substantially VertrinA connection therewith. j The incoming fuel and air flows eontactinglyrv obvio/.5s that changes may cally downward direction to one side oflsaid outlet and adjacent an'upright wall of the' fuel admission and opposite the fuel and flame stream. K.

4. A furnace for burning et in an upper part and having means for admitting the fuel .in an upper jpart of the'chamber inl adownward direction having an' outl V-Vwhereby, the fueland flame stream takes a fsomewhat U-sha'ped `course through -thef and'having means for controlpulverized fuel chamber, 'and having means. for eontrollably admitting air for combustion at aV of successive levels below the -level of 'fuel admission and opposite the fuell and flame itream at lthree contiguous sides of the cham- 5.'A furnace forburning pulverized fuell having an outlet in an upper pai-tand having means forfadmitting the fuel in an upper part of the chamber in a substantially vertically.downwarddirection.to one side of said 'outlet and adjacent an upright wall of the furnace 'whereby' the fuel andv flame `stream takes a somewhat U-shaped`course through the ch mber, and having means for controllably admittingair for combustionl at avplurality of successive levelsl below the level of fuel admission, said chamber having 'means for creating a cooling zone intermediate the zone of combustion and the place ofhash deposit, -which zone acts to cool the as v sufficiently toy prevent the ash.

(SQA furnace for burning pulverizedfuel having an` outlet in an upper part and hav,

7. A furnace for burning pulverized fuel having an outlet in-an for introducing the'fuel in a substantially vertically downward direction to one side of said outlet and adjacent an upright wall of the furnace' whereby the fuel andy flame stream takes .through the chamber, and having means for creating a cooling zone marginally of the plurality particles precipitating therethroughsubstantial. fusion of j.

upper part, and means -a"somewhat U-shaped course' i zone of'eombustion for cooling refuse particles leaving .the fuel and flame stream'to pass through such zone, and boiler tubes exposed tothe outlet flow.

.8. A furnace for burning pulver-ized .fuel

having al1-outlet in an upper part, and meansa substantially `for introducing the fuel 1n to one side of vertically downward direction 5 the outlet whereby the fuel and flame stream takes a somewhat U-shaped course through the chamber, and having means for creating a cooling zone marginally of the zone of.

combustion' for cooling refuse particles leav- 10 ing the fuel and flame stream to pass through such zone, and boiler tubes exposed to the outlet flow, and means for providing heat whereby complete combustion of the fuel is sus- In testimony that they their names hereunder.

.JOHN EfMUHLFELn VIRGINIUS z. oARAoRIsTI. 

